Use and effectiveness of iodine tablets

An accident at a nuclear power plant may result in the release of radioactive materials – including radioactive iodine. If radioactive iodine is inhaled or enters the body via food or beverages, it may accumulate in the thyroid and encourage the development of thyroid cancer.

If affected individuals take non-radioactive iodine in the form of high-dose iodine tablets (also known as potassium iodide tablets) at the appropriate time, they can prevent radioactive iodine from accumulating in their thyroid: the tablets serve to saturate the thyroid with non-radioactive iodine so that it can no longer take up radioactive iodine at a later stage. This is referred to as iodine thyroid blocking.

Only take iodine tablets when expressly asked to do so

High-dose iodine tablets should only be taken once this is expressly requested by the civil protection authorities – and only in the dose indicated by the authorities.

As the use of high-dose iodine tablets can lead to side effects, self-medication is strongly advised against.

In principle, a single administration is sufficient. Further tablets should be taken only if recommended by the civil protection authority.

Timing is crucial

To have the desired effect, the tablets must be taken at the correct time.

• If iodine tablets are taken too early, the non-radioactive iodine can be depleted again when radioactive iodine is absorbed. The protection would therefore have been in place too soon and would not be sufficient.
• If iodine tablets are taken too late, the thyroid might already have absorbed radioactive iodine. The protection would therefore have come too late.
• Ideally, iodine tablets should be taken one hour before the arrival of the radioactive air masses.

In the event of an emergency, the appropriate time of administration is therefore announced by the civil protection authorities via the media.

Regional recommendations on taking iodine tablets

Whether people are asked to take high-dose iodine tablets after a nuclear accident depends on the distribution of the radioactive iodine cloud. This in turn depends on:

• how much radioactive iodine is released
• the distance from the site of the accident
• the wind and weather conditions

For example, high-dose iodine tablets are distributed in the vicinity of nuclear power plants in the event of a nuclear accident. The size of this area depends on the severity of the accident. In the event of an accident involving a significant release of radioactive iodine, the use of iodine tablets may be recommended for adults within 100 kilometres and for children throughout Germany.

Iodine tablets are advisable for people up to the age of 45, including pregnant women and children

In principle, all people up to the age of 45 in the affected areas should take high-dose iodine tablets, with the correct dosage varying according to age.

• As the thyroid is particularly sensitive in children and young people up to the age of 18, it is especially important for children and young people to take iodine tablets.
• For pregnant women, taking iodine tablets particularly helps to protect the unborn child.

People older than 45 years are advised against taking iodine tablets for iodine thyroid blocking. For them, the risk of side effects outweighs the benefits of avoiding an increased risk of thyroid cancer.

Iodine tablets are risky for individuals with thyroid diseases

Taking high-dose iodine tablets is also associated with risks to health. In Germany, a considerable proportion of adults suffer from latent hyperthyroidism – that is, overactivity of the thyroid without signs of disease. This latent hyperthyroidism can evolve into symptomatic hyperthyroidism due to the intake of high doses of potassium iodide. Symptoms can include everything up to acute cardiovascular failure.

Other known side effects include sensitivity to iodine.

Individuals who are known to suffer from thyroid disease should only take iodine tablets after consulting the doctor providing treatment.

Where can iodine tablets be found?

In Germany, the federal states are responsible for the storage and distribution of high-dose iodine tablets. Depending on the federal state, the high dosage iodine tablets are either stored in the immediate vicinity of a nuclear power plant, are distributed to all households in advance or are stored locally, for example at town halls or local fire stations.

In addition, over 180 million iodine tablets are stored at various locations across Germany. Should an incident occur, these tablets are handed out to the population at fire stations, town halls, pharmacies or well-known polling stations.

After an accident citizens are promptly requested by authorities via different media to collect their tablets at these points of issue. Please consult your civil protection authority for organisational information and details of planned procedures.